| 释义 |
- Cadmium-113m
- List of isotopes Notes
- References
{{more citations needed|date=May 2018}}{{infobox cadmium isotopes}}Naturally occurring cadmium (48Cd) is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays were never observed, due to extremely long half-lives. The two natural radioactive isotopes are 113Cd (beta decay, half-life is 8.04 × 1015 years) and 116Cd (two-neutrino double beta decay, half-life is 2.8 × 1019 years). The other three are 106Cd, 108Cd (double electron capture), and 114Cd (double beta decay); only lower limits on their half-life times have been set. At least three isotopes—110Cd, 111Cd, and 112Cd—are absolutely stable. Among the isotopes absent in the natural cadmium, the most long-lived are 109Cd with a half-life of 462.6 days, and 115Cd with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives that are less than 2.5 hours and the majority of these have half-lives that are less than 5 minutes. This element also has 12 known meta states, with the most stable being 113mCd (t1/2 14.1 years), 115mCd (t1/2 44.6 days) and 117mCd (t1/2 3.36 hours). The known isotopes of cadmium range in atomic mass from 94.950 u (95Cd) to 131.946 u (132Cd). The primary decay mode before the second most abundant stable isotope, 112Cd, is electron capture and the primary modes after are beta emission and electron capture. The primary decay product before 112Cd is element 47 (silver) and the primary product after is element 49 (indium). Cadmium-113m {{Medium-lived fission products}}Cadmium-113m is a cadmium radioisotope and nuclear isomer with a half-life of 14.1 years. In a normal thermal reactor, it has a very low fission product yield, plus its large neutron capture cross section means that most of even the small amount produced is destroyed in the course of the nuclear fuel's burnup; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides{{which|date=May 2018}} will produce 113mCd at higher yields. List of isotopes nuclide
symbol | Z(p) | N(n) |
isotopic mass (u)
| half-life[1] | decay
mode(s)[2][3] | daughter
isotope(s)[4] | nuclear
spin and
parity | representative
isotopic
composition
(mole fraction) | range of natural
variation
(mole fraction) | | excitation energy |
|---|
| 95Cd | 48 | 47 | 94.94987(64)# | 5# ms | 9/2+# | | 96Cd | 48 | 48 | 95.93977(54)# | 1# s | β+ | 96Ag | 0+ | | 97Cd | 48 | 49 | 96.93494(43)# | 2.8(6) s | β+ (>99.9%) | 97Ag | 9/2+# | | | | β+, p (<.1%) | 96Pd | | 98Cd | 48 | 50 | 97.92740(8) | 9.2(3) s | β+ (99.975%) | 98Ag | 0+ | | | | β+, p (.025%) | 97Ag | | 98mCd | 2427.5(6) keV | 190(20) ns | 8+# | | 99Cd | 48 | 51 | 98.92501(22)# | 16(3) s | β+ (99.78%) | 99Ag | (5/2+) | | | | β+, p (.21%) | 98Pd | | β+, α (10−4%) | 94Rh | | 100Cd | 48 | 52 | 99.92029(10) | 49.1(5) s | β+ | 100Ag | 0+ | | 101Cd | 48 | 53 | 100.91868(16) | 1.36(5) min | β+ | 101Ag | (5/2+) | | 102Cd | 48 | 54 | 101.91446(3) | 5.5(5) min | β+ | 102Ag | 0+ | | 103Cd | 48 | 55 | 102.913419(17) | 7.3(1) min | β+ | 103Ag | 5/2+ | | 104Cd | 48 | 56 | 103.909849(10) | 57.7(10) min | β+ | 104Ag | 0+ | | 105Cd | 48 | 57 | 104.909468(12) | 55.5(4) min | β+ | 105Ag | 5/2+ | | 106Cd | 48 | 58 | 105.906459(6) | Observationally Stable[5] | 0+ | 0.0125(6) | | 107Cd | 48 | 59 | 106.906618(6) | 6.50(2) h | β+ | 107mAg | 5/2+ | | 108Cd | 48 | 60 | 107.904184(6) | Observationally Stable[6] | 0+ | 0.0089(3) | | 109Cd | 48 | 61 | 108.904982(4) | 461.4(12) d | EC | 109Ag | 5/2+ | | 109m1Cd | 59.6(4) keV | 12(2) µs | 1/2+ | | 109m2Cd | 463.0(5) keV | 10.9(5) µs | 11/2 | | 110Cd | 48 | 62 | 109.9030021(29) | Stable | 0+ | 0.1249(18) | | 111Cd[7] | 48 | 63 | 110.9041781(29) | Stable | 1/2+ | 0.1280(12) | | 111mCd | 396.214(21) keV | 48.50(9) min | IT | 111Cd | 11/2− | | 112Cd[7] | 48 | 64 | 111.9027578(29) | Stable | 0+ | 0.2413(21) | | 113Cd[7][8] | 48 | 65 | 112.9044017(29) | 8.04(5)×1015 y | β− | 113In | 1/2+ | 0.1222(12) | | 113mCd[7] | 263.54(3) keV | 14.1(5) y | β− (99.86%) | 113In | 11/2− | | | | IT (.139%) | 113Cd | | 114Cd[7] | 48 | 66 | 113.9033585(29) | Observationally Stable[9] | 0+ | 0.2873(42) | | 115Cd[7] | 48 | 67 | 114.9054310(29) | 53.46(5) h | β− | 115mIn | 1/2+ | | 115mCd | 181.0(5) keV | 44.56(24) d | β− | 115mIn | (11/2)− | | 116Cd[7][8] | 48 | 68 | 115.904756(3) | 2.8(2)×1019 y | β−β− | 116Sn | 0+ | 0.0749(18) | | 117Cd | 48 | 69 | 116.907219(4) | 2.49(4) h | β− | 117mIn | 1/2+ | | 117mCd | 136.4(2) keV | 3.36(5) h | β− | 117mIn | (11/2)− | | 118Cd | 48 | 70 | 117.906915(22) | 50.3(2) min | β− | 118In | 0+ | | 119Cd | 48 | 71 | 118.90992(9) | 2.69(2) min | β− | 119mIn | (3/2+) | | 119mCd | 146.54(11) keV | 2.20(2) min | β− | 119mIn | (11/2−)# | | 120Cd | 48 | 72 | 119.90985(2) | 50.80(21) s | β− | 120In | 0+ | | 121Cd | 48 | 73 | 120.91298(9) | 13.5(3) s | β− | 121mIn | (3/2+) | | 121mCd | 214.86(15) keV | 8.3(8) s | β− | 121mIn | (11/2−) | | 122Cd | 48 | 74 | 121.91333(5) | 5.24(3) s | β− | 122In | 0+ | | 123Cd | 48 | 75 | 122.91700(4) | 2.10(2) s | β− | 123mIn | (3/2)+ | | 123mCd | 316.52(23) keV | 1.82(3) s | β− | 123In | (11/2−) | | | | IT | 23Cd | | 124Cd | 48 | 76 | 123.91765(7) | 1.25(2) s | β− | 124In | 0+ | | 125Cd | 48 | 77 | 124.92125(7) | 0.65(2) s | β− | 125mIn | (3/2+)# | | 125mCd | 50(70) keV | 570(90) ms | β− | 125In | 11/2−# | | 126Cd | 48 | 78 | 125.92235(6) | 0.515(17) s | β− | 126In | 0+ | | 127Cd | 48 | 79 | 126.92644(8) | 0.37(7) s | β− | 127mIn | (3/2+) | | 128Cd | 48 | 80 | 127.92776(32) | 0.28(4) s | β− | 128In | 0+ | | 129Cd | 48 | 81 | 128.93215(32)# | 242(8) ms | β− (>99.9%) | 129In | 3/2+# | | | | IT (<.1%) | 129Cd | | 129mCd | 0(200)# keV | 104(6) ms | 11/2−# | | 130Cd | 48 | 82 | 129.9339(3) | 162(7) ms | β− (96%) | 130In | 0+ | | | | β−, n (4%) | 129In | | 131Cd | 48 | 83 | 130.94067(32)# | 68(3) ms | 7/2−# | | 132Cd | 48 | 84 | 131.94555(54)# | 97(10) ms | 0+ |
1. ^Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
2. ^{{cite web |url=http://www.nucleonica.net/unc.aspx |title=Universal Nuclide Chart |publisher=nucleonica |registration=yes}}
3. ^Abbreviations:
EC: Electron capture
IT: Isomeric transition
4. ^Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
5. ^Believed to decay by β+β+ to 106Pd with a half-life over 4.1×1020 years
6. ^Believed to decay by β+β+ to 108Pd with a half-life over 4.1×1017 years
7. ^1 2 3 4 5 6 Fission product
8. ^1 Primordial radionuclide
9. ^Believed to undergo β−β− decay to 114Sn with a half-life over 6.4×1018 years
Notes - The precision of the isotope abundances and atomic mass is limited through variations. The given ranges should be applicable to any normal terrestrial material.
- Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
- Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
- Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.
- Hyperdeformation is predicted to be found in 107Cd.
References - Isotope masses from:
- Isotopic compositions and standard atomic masses from:
- {{CAWIA 2003}}
- {{CIAAW 2005}}
- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- {{NUBASE 2003}}
- {{NNDC}}
- {{CRC85|chapter=11}}
{{Navbox element isotopes}} 3 : Cadmium|Isotopes of cadmium|Lists of isotopes by element |